The chemicals in gel coat are corrosive. CFS Fiberglass states that protective covering should be worn, since the chemicals cause skin irritation. The catalyst is methyl ethyl ketone peroxide (MEKP), which is also a corrosive chemical. A catalyst is a chemical that aids in the curing/hardening process. The overall recommendation by CFS Fiberglass is to never let the chemicals come in contact with your skin, eyes or mouth. This is easily accomplished by wearing safety glasses, gloves and coveralls.
During the application process, vapors are released. Multi-Tech Products states on its material safety data sheet that the vapors are a respiratory irritant. If overexposure occurs, the vapors enter the blood stream. When this happens the nervous system is affected, resulting in headaches, confusion, insensibility and nausea. Multi-Tech Products recommends you get fresh air or oxygen and call medical personnel if you inhale the vapors. The prevention of overexposure is simple. When using gel coat you should wear a respirator designed for hazardous vapors.
The chemicals in liquid gel coat are flammable. CFS Fiberglass recommends extinguishing all flames or possible ignition sources. Do not smoke or use electric heaters when applying gel coat. Also, in the process of curing, considerable heat is generated by the chemical reaction. If gel coat and the catalyst were mixed in a cup, the cup should not be thrown away immediately, since it could catch on fire. CFS Fiberglass recommends letting the cup sit in a fireproof area until it has cooled down.
Uncured gel coat is an environmental hazard. Small spills can be cleaned up with dirt or cat litter. For larger spills, contact emergency personnel who have the expertise to deal with large spill containment. CFS Fiberglass states that the catalyst should not be cleaned up with a mop. Instead, flush it with large quantities of water to dilute the chemical.